Even before the recent dramatic increases in the price of gold, there had been an effort by workers in the art to develop gold alloys having the appearance of 10, 12, 14, and 18 karat gold but with a much lower gold content. However, many problems have been encountered in achieving the desired durability, workability, corrosion and tarnish resistance and particularly in simulating the appearance of white gold alloys as the percentages of gold have been decreased to provide a lower cost substitute for 10 and higher karat gold. Representative of the efforts of prior art workers are the following patents, U.S. Pat. Nos. 2,460,595; 2,279,284; 4,012,228; and 4,264,359.
The problems of providing a truly low cost substitute for 10 or higher karat white gold having the desired color, hue and luster as well as other desirable properties such as resistance to corrosion and tarnishing as well as a reduction of surface roughness have heretofore not been overcome in the prior art.
For example, the alloy disclosed in the Reich patent, U.S. Pat. No. 2,460,595 is very brittle and thus not useful for jewelry, has a relatively high melting point because of the high palladium content, and cannot be satisfactorily sized with conventional solders. Moreover, white gold as we know it today has a slight but definitely yellow hue. The Reich alloy lacks this hue, i.e., it is too "white."